Robot controller and control method

ABSTRACT

It is an object to provide a robot control system and a method of controlling the same having an outstanding extensibility, maintainability, and reliability in the system. A main control unit  1  and an auxiliary control unit  2  control a manipulator  4  actuated by a servo motor. The main control unit  1  and the auxiliary control unit  2  are so composed as to make a data communication via communication means  5 . In addition, the main control unit  1  is connected to a centralized control unit  3  through communication means  7 . The centralized control unit  3  supervises and controls concentrically a plurality of robot control apparatuses connected thereto.

THIS APPLICATION IS A U.S. NATIONAL PHASE APPLICATION OF PCTINTERNATIONAL APPLICATION PCT/JP99/04426.

FIELD OF THE INVENTION

The present invention relates to a robot control apparatus and itsmethod for controlling a teaching, operation, and the like of anindustrial robot. In particular, the invention relates to a robotcontrol apparatus having an outstanding reliability and maintainability,and a great extensibility.

BACKGROUND OF THE INVENTION

FIG. 7 is a general architectural view of a robotic system of the priorart, and FIG. 8 is a block diagram of an exemplary structure of a robotcontrol apparatus of the prior art. A manipulator 4 is controlled by arobot control apparatus 30, as shown in FIG. 7. The robot controlapparatus 30 of the prior art comprises a main control circuit 301 forperforming a centralized control of a robot, a servo controller circuit302 for controlling a servo motor, and a servo amplifier 303 for drivingthe servo motor, all in one unit, as show in FIG. 8. The main controlcircuit 301 is composed of a processor (CPU) 301 a, a random-accessmemory (RAM) 301 b and a read-only memory (ROM) 301 c. The CPU 301 aperforms various kinds of computations for control of the robot using anumerous data such as a teaching data, a coordinate system data, and thelike of the robot stored in the RAM 301 b, composed as a nonvolatilememory in a portion thereof, according to a system program stored in theROM 301 c. The main control circuit 301 aand a servo controller circuit302 are connected by a data bus 304, and an operating command from themain control circuit 301 is converted by the servo controller circuit302 into a command for servo control, with which a servo amplifier 303controls a servo motor 40 for operating each axle of a robotmanipulator. An I/O interface 305 is connected to the data bus 300 forexecuting an I/O control of an external apparatus such as a robot handand the like, not shown in the figure. Furthermore, a serial interface306 is also connected to the data bus 300, and a teaching device forteaching a movement of the robot is connected to the serial interface306.

Since such a robot control apparatus of the prior art has been composedas above, the main control circuit has been disposed in vicinity of theservo amplifier, which tends to generate heat and electric noise.Moreover, there is often such a case wherein the control apparatusitself is disposed in vicinity of the manipulator performing physicalworks, and used under an adverse environment of high temperatures anddusty particles, etc. Since there is a possibility for the main controlcircuit, which governs control of the robot, to cause a malfunction orto receive damages due to the foregoing internal and external factors,there requires appropriate measures to improve cooling, a noiseimmunity, dust-tightness, and so on in order to prevent them.

Furthermore, as the CPU in the main control circuit takes charge ofvarious computations such as a locus generation, and calculation of anacceleration and deceleration of the robot, an operational performanceof the robot depends upon a processing capacity of the CPU. Therefore,it is necessary to increase a capacity of the main control circuit,including this CPU, in order to improve a kinetic performance of therobot. However, a change of the CPU necessitates changes for a width ofthe bus, a transmission speed, a transmission mode, and so on of thedata bus. In addition, it also requires modification of the servocontroller circuit, the I/O interface, the serial port, etc. connectedto the data bus.

Next, since the system program for the robot is stored in the ROM withinthe robot control apparatus, it is necessary to replace the ROM in orderto renew the system program. However, if the robot control apparatus isinstalled at a high location, in a narrow space, or the like, areplacement of the ROM gives rise to a problem that it is difficult toensure safety of a worker as the workability is extremely poor.

On the other hand, the teaching data, etc. of the robot are stored inthe RAM composed of a nonvolatile memory. However, since the RAM needsto be kept energized with a battery and the like at all the time inorder for it to maintain the stored data, it is necessary to back upthis data to another memory device to prevent a loss of the data due todegradation and the like of the battery. Back up of the data can beaccomplished by connecting the robot control apparatus to a personalcomputer via an interface such as a serial port, and then to an externalrecording device. However, a task required for the backup is complex,and it takes a long working hours, giving rise to another problem.Moreover, this task of backup also has a problem common to theafore-said replacement of the ROM that it is difficult to ensure safetyof the worker, as the workability is extremely poor if the robot controlapparatus is installed at a high location, in a narrow space, etc.

In addition, it is not easy to connect and use general purposeperipheral devices such as a display device like a monitor, etc., aninput device like a keyboard, etc., and a telecommunications device likea network, etc. to the data bus and to the robot control apparatus,since architecture of the hardware such as the main control circuit andthe data bus is of customizes composition. It is therefore necessary toprepare a separate custom-made interface individually for connecting therobot control apparatus to each of these devices, in order to use them.This presents still another problem that makes it difficult to expandthe system freely, since there is a great deal of restriction to thekind of peripheral devices that can be connected and used with the robotcontrol apparatus.

The present invention has been made to obviate the above-cited problems,and has an object to provide a robot control apparatus and a methodthereof having a great extensibility and maintainability, as well as anoutstanding reliability in its system.

SUMMARY OF THE INVENTION

A robot control apparatus of the present invention comprises a servoamplifier for controlling a driving source of a robot, an auxiliarycontrol unit for outputting a driving control command to the servoamplifier, and a main control unit provided separately from theauxiliary control unit for outputting a control command for an operationof the robot to the auxiliary control unit through communication means.A method of controlling the robot comprises a step of generating a robotcontrol command, and a step of outputting the control command forcontrolling the robot through the communication means, both performed inthe main control unit. On the other hand, the auxiliary control unittakes a step of receiving the robot control command from the maincontrol unit, a step of converting the command into another command tobe transmitted to the servo amplifier, and a step of transmitting theconverted command to the servo amplifier.

Also, the robot control apparatus of the present invention is providedwith a nonvolatile data storage device and an external interface forconnecting with a data bus in the main control unit.

Further, the robot control apparatus of the present invention isprovided, also in the main control unit, with an auxiliary storagedevice for backup of data stored in the data storage unit of the maincontrol unit.

In the robot control apparatus of the present invention, the maincontrol unit transmits to the auxiliary control unit, a robot positioncontrol command calculated by the main control unit based on a teachingposition data for the robot stored in the data storage device of themain control unit.

Furthermore, in the robot control apparatus of the present invention, aservo controller circuit performs an ON/OFF control of the servoamplifier based on an ON/OFF control signal for the servo amplifiertransmitted from the main control unit to the auxiliary control unit.The method of controlling the robot in this process includes a step ofoutputting the ON/OFF control signal for the servo amplifier from themain control unit to the auxiliary control unit.

Moreover, in the robot control apparatus of the present invention, theservo controller circuit renders the servo amplifier to temporarilysuspend and to restart its control based on a temporary suspensionsignal and a restart signal for the robot operation transmitted from themain control unit to the auxiliary control unit. The method ofcontrolling the robot in this process includes a step of outputting thetemporary suspension signal and the restart signal of the robotoperation from the main control unit to the auxiliary control unit.

Also, the robot control apparatus of the present invention is providedwith a timer means in the auxiliary control unit, and a robot suspensionmeans for deactivating the servo amplifier, when a non-receiving timefor the robot control command to be transmitted by the main control unitbecomes equal to or longer than a pre-established period of time. Themethod of controlling the robot in this process includes a step ofcounting time in the auxiliary control unit for not receiving a commandfrom the main control unit, a step of making a determination of atimeout when the non-receiving time becomes equal to or longer than thepre-established time period, and a step of deactivating the servoamplifier if a timeout is determined.

Furthermore, the robot control apparatus of the present invention isprovided with a robot suspension means for deactivating the servoamplifier, if the main control unit does not return to the auxiliarycontrol unit a signal corresponding to a prior signal that the auxiliarycontrol unit has transmitted to the main control unit. The method ofcontrolling the robot in this process includes a step for the auxiliarycontrol unit to output a signal to the main control unit, a step ofreceiving a response signal from the main control unit, a step ofverifying whether the response signal is a signal corresponding to thetransmitted signal, and a step of deactivating the servo amplifier, ifthe response signal does not correspond to the transmitted signal.

Moreover, the robot control apparatus of the present invention isprovided with a timer means in the main control unit, and adetermination means also in the main control unit for determining eitherthe auxiliary control unit or the communication means is out of order,if the main control unit does not receive a signal from the auxiliarycontrol unit for a pre-established period of time or longer. The methodof controlling the robot in this process includes a step of countingtime in the main control unit for not receiving a signal from theauxiliary control unit, a step of making a determination of a timeoutwhen the non-receiving time becomes equal to or longer than thepre-established time period, and a step of determining either theauxiliary control unit or the communication means is out of order if atimeout is determined.

Further, the robot control apparatus of the present invention isprovided with a determination means in the main control unit fordetermining either the auxiliary control unit or the communication meansis out of order, if a signal corresponding to the signal transmitted tothe auxiliary control unit from the main control unit is not returnedfrom the auxiliary control unit. The method of controlling the robot inthis process includes a step for the main control unit to output asignal to the auxiliary control unit, a step of receiving a responsesignal from the auxiliary control unit, a step of verifying whether theresponse signal is a signal corresponding to the transmitted signal, anda step of determining either the auxiliary control unit or thecommunication means is out of order, if the response signal does notcorrespond to the transmitted signal.

Furthermore, the robot control apparatus of the present invention isprovided with a centralized control unit connected to the main controlunit via communication means, a timer means in the centralized controlunit, and a determination means also in the centralized control unit fordetermining either the main control unit or the communication means isout of order, if the centralized control unit does not receive a signalfrom the main control unit for a pre-established period of time orlonger. The method of controlling the robot in this process includes astep of counting time in the centralized control unit connected to themain control unit via the communication means for not receiving a signaltransmitted from the main control unit, a step of making a determinationof a timeout when the non-receiving time becomes equal to or longer thanthe pre-established time period, and a step of determining either themain control unit or the communication means is out of order if atimeout is determined.

Moreover, the robot control apparatus of the present invention isprovided with a centralized control unit connected to the main controlunit via the communication means, and a determination means in thecentralized control unit for determining that the main control unit orthe communication means is out of order, if a signal corresponding tothe signal transmitted to the main control unit from the centralizedcontrol unit is not returned from the main control unit. The method ofcontrolling the robot in this process includes a step for thecentralized control unit connected to the main control unit via thecommunication means to output a signal to the main control unit, a stepof receiving a response signal from the main control unit, a step ofverifying whether the response signal is a signal corresponding to thetransmitted signal, and a step of determining either the main controlunit or the communication means is out of order, if the response signaldoes not correspond to the transmitted signal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general architectural view of a robot control apparatus ofthe present invention;

FIG. 2 is a block diagram depicting a structure of a main control unitand an auxiliary control unit of the present invention;

FIG. 3 is a flow chart depicting a method of the present invention forcontrolling a robot;

FIG. 4 is another flow chart depicting a method of the present inventionfor controlling a robot;

FIG. 5 is still another flow chart depicting a method of the presentinvention for controlling a robot;

FIG. 6 is yet another flow chart depicting a method of the presentinvention for controlling a robot;

FIG. 7 is a general architectural view of a robotic system of the priorart; and

FIG. 8 is a block diagram depicting a structure of a robot controlapparatus of the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A robot control apparatus of the present invention comprises a servoamplifier for controlling a driving source of a robot, an auxiliarycontrol unit for outputting a driving control command to the servoamplifier, and a main control unit having a main control circuit forcontrolling the robot, for outputting a control command for operatingthe robot to the auxiliary control unit through communication means, andprovided separately from the auxiliary control unit. Accordingly, sincethe main control unit can be disposed in a location isolated from theservo amplifier, which generates intense heat and electrical noises, andalso from a manipulator, which is used under an adverse environment suchas high temperatures and dusty particles, it is able to avoid anerroneous operation of the robotic system and from receiving damages dueto an influence of the adverse environment.

Further, since the main control unit and the auxiliary control unit areseparate from each other, an improvement of operational performance ofthe robot can be achieved easily by modifying only the main controlunit, without subjecting the entire control apparatus to a modification.

In addition, a task of renewing a system program of the robot can becarried out quite easily, since the system program of the robot isstored in a data storage device such as a hard disk, a flash memory, andthe like in the main control unit, and the main control unit is disposedin a remote place from the manipulator. Besides, since the teachingdata, etc. of the robot are also stored in the data storage device suchas the hard disk, the flash memory, and the like in the main controlunit, a battery, etc. needs not be used to maintain the data. Moreover,since there is also an auxiliary storage device provided in the maincontrol unit for backup of the data, the task of backing-up the data canbe accomplished easily and quickly, thereby enabling it to be preparedfor an unforeseeable loss of the data.

Further, there is adopted a general-purpose data bus and ageneral-purpose interface as a data bus of the main control unit. Thiscan readily allow use of general purpose peripheral devices such as adisplay device like a monitor, etc., an input device like a keyboard,etc., and a communications device like a network, etc. by connectingthem to the robot control apparatus, thereby enabling an expansion ofthe system freely. In addition, this also makes it possible toconcentrically supervise and control a plurality of the robot controlapparatuses using communication means such as the network, since therobot control apparatuses can be connected with generic network boardsin the case of a system operating a plurality of robots.

The following will describe an exemplary embodiment of the presentinvention with reference to the drawings. An overall architecture of therobot control apparatus of this invention is shown in FIG. 1. In thisrobot control apparatus, a main control unit 1 and an auxiliary controlunit 2 control a manipulator 4 actuated by a servo motor. The maincontrol unit 1 and the auxiliary control unit 2 are so composed thatthey communicate data through a communication means 5. The main controlunit 1 is also connected to a centralized control unit 3 through acommunication means 7. The centralized control unit 3 concentricallysupervises a plurality of the robot control apparatuses connectedthereto, and controls them.

FIG. 2 is a block diagram showing an exemplary structure of the maincontrol unit 1 and the auxiliary control unit 2. The main control unit 1comprises a main control circuit 110, a data storage device 101, anauxiliary storage device 102, an interface 103 for communication withthe auxiliary control unit, an interface 108 for a local area network(LAN), serving as a communication means with the centralized controlunit 3, and so on. These are connected to a PCI bus 100, used widely asthe general-purpose data bus. In addition, the main control unit is alsoprovided with a serial interface 104 and a parallel interface 105 of theRS-232C type used widely as external interfaces of personal computers,which allows connection and use readily of a variety of peripheraldevices. Moreover, there are provided an interface 106 for a monitor andan interface 107 for a keyboard connected to the data bus 100 serving asman-machine interfaces. These interfaces employ the same connectors asused generally for personal computers for a connection between the databus 100 and each interface, and between each interface and theperipheral device connected thereto, so as to increase an extensibilityof the robot control apparatus. Although the PCI bus is employed as thedata bus 100 in this exemplary embodiment, an equivalent effect can beachieved even with an ISA bus, which is also used as equally commonly asthe PCI bus.

The data storage device 101 consisting of a hard disk drive stores ateaching data, a system data, a system program, and so on for the robot.A CPU in the main control circuit 110 loads necessary data among theminto a memory in the main control circuit 110, and computes a positioncontrol data, etc. of the robot. The auxiliary storage device 102consisting similarly of a hard disk drive backs up the data stored inthe data storage device 101, to be prepared for an unforeseeable loss ofthe data. The hard disk drives wherein the data can be kept without asupply of electricity are used for the data storage device 101 and theauxiliary storage device 102. However, their reliability can be furtherincreased by adopting flash memories that are capable of operating undercomparatively high temperatures without requiring a mechanical movement.When it becomes necessary to read the data in the data storage device101 and the auxiliary storage device 102, or to renew the data from theoutside, they can be accomplished remotely from the centralized controlunit through the LAN interface 108. Alternatively, it can beaccomplished through a floppy disk by connecting a floppy disk drive orthe like to the data bus 100, although not shown in the figure. It isneedless to note that the foregoing structure can be realized moreeasily with a personal computer as the main control unit.

On the other hand, the auxiliary control unit 2 comprises acommunication interface 203 for connecting to a data bus 200, a servocontroller circuit 201, a servo amplifier 202, an I/O interface 204, anda serial interface 205. The data bus is able to make a datacommunication with the main control unit 1 through the communicationinterface 203 and communication means 5 comprising an RS-232C typeserial communication cable. The I/O interface 204 is connected with anend effector such as a robot hand, though not shown in the figure, andthe serial interface 205 is connected with a teaching device 12 forexecuting a task of teaching for the robot.

The main control circuit 110 of the main control unit 1 controls theauxiliary control unit with a step 50 a of generating a robot controlcommand and a step 50 b of transmitting the command to the servocontroller circuit 201 in the auxiliary control unit 2, as shown in FIG.3. The servo controller circuit 201 in the auxiliary control unit 2controls the servo amplifier 202 with a step 51 a of receiving the robotcontrol command from the main control unit 1, a step 51 b of convertingthe received command into another command for controlling the servoamplifier, and a step 51 b of transmitting the servo control command tothe servo amplifier, as shown in FIG. 4. The servo controller circuit201 controls a servomotor 40 connected the servo amplifier 202. The maincontrol unit 1 transmits to the auxiliary control unit 2 the robotcontrol command such as a positional command of the robot, an ON/OFFcommand for the servo amplifier, and a temporary suspension and restart,etc.

The auxiliary control unit 2 is provided with a robot suspending meansfor deactivating the servo amplifier 202, using a method of controllingthe robot, which comprises a step 52 a of counting a non-receiving timeTu of the robot control command to be transmitted by the main controlunit with a timer means, not shown in the figure, a step 52 b of makinga determination as to whether the Tu is equal to or longer than apre-established determination time period To (a timeout), and a step 52c of carrying out an error handling, if a determination of timeout ismade, as shown in FIG. 5.

The auxiliary control unit 2 is also provided with another robotsuspending means for deactivating the servo amplifier 202, in case ofmaking an error handling, using a method of controlling the robot, whichcomprises a step 53 a of transmitting a signal from the auxiliarycontrol unit 2 to the main control unit 1, a step 53 b of receiving aresponse signal returned from the main control unit 1 to the auxiliarycontrol unit 2, a step 53 c of verifying whether the response signal isa signal corresponding to the transmitted signal, and a step 53 d ofcarrying out the error handling, if the response signal is anomalous, asshown in FIG. 6.

On the other hand, the main control unit 1 is provided with adetermination means for determining either the auxiliary control unit 2or the communication means is out of order, if an error determination ismade, by adopting a method of controlling the robot, which comprises astep 52 a of counting a non-receiving time Tu of the response signal tobe transmitted by the main control unit with a timer means provided inthe main control unit 1, though not shown in the figure, a step 52 b ofmaking a determination as to whether the Tu is equal to or longer than apre-established determination time period To (a timeout), and a step 52c of carrying out an error handling, if a determination of timeout ismade, as shown in FIG. 5.

Also, the main control unit 1 is provided with another determinationmeans for determining either the auxiliary control unit 2 or thecommunication means 5 is out of order, if an error determination ismade, by adopting a method of controlling the robot, which comprises astep 53 a of transmitting a signal from the main control unit 1 to theauxiliary control unit 2, a step 53 b of receiving a response signalreturned from the auxiliary control unit 2 to the main control unit 1, astep 53 c of verifying whether the response signal is a signalcorresponding to the transmitted signal, and a step of carrying out theerror handling, if the response signal is anomalous, as shown in FIG. 6.

Furthermore, the robot control system of the present invention isprovided with a centralized control unit 3 connected to the main controlunit 1 via a communication means 7 using a LAN, and the centralizedcontrol unit 3 is provided with a timer means which is not shown in thefigure. The centralized control unit 3 is provided further with adetermination means for determining either the main control unit or thecommunication means is out of order, if an error determination is made,by adopting a method of controlling the robot, which comprises a step 52a of counting a non-receiving time Tu of the robot control command to betransmitted by the main control unit, a step 52 b of making adetermination as to whether the Tu is equal to or longer than apre-established determination time period To (a timeout), and a step 52c of carrying out an error handling, if a determination of timeout ismade, as shown in FIG. 5.

The centralized control unit 3 is provided with another determinationmeans for determining either the main control unit 1 or thecommunication means 7 is out of order, if an error determination ismade, by adopting a method of controlling the robot, which comprises astep 53 a of transmitting a signal from the centralized control unit 3to the main control unit 1, a step 53 b of receiving a response signalreturned from the a main control unit 1 to the centralized control unit3, a step 53 c of verifying whether the response signal is a signalcorresponding to the transmitted signal, and a step 53 d of carrying outan error handling, if the response signal is anomalous, as shown in FIG.6.

An RS-422 type serial cable, and optical communication means using anoptical communication cable or the infrared rays may be used as theabove-described communication means 5 and 7, instead of thecommunication means using the RS-232C type and LAN, in order to obtainthe similar effectiveness. An optical communication cable can be adoptedas a very effectual means especially in an environment where electricalnoises are considerably high.

INDUSTRIAL APPLICABILITY

In the present invention, as has been described above, since a maincontrol unit can be disposed in a manner to be isolated from a servoamplifier, which generates heat and electrical noises, and also from amanipulator used under an adverse environment such as high temperaturesand dusty particles, it is able to avoid an erroneous operation of arobotic system and from receiving damages due to an influence of theadverse environment. In addition, an improvement of operationalperformance of the robot can be attained easily by modifying only themain control unit.

In addition, a task of renewing a system program of the robot can bemade quite readily, since the system program of the robot is stored in adata storage device such as a hard disk, a flash memory, and the like inthe main control unit, and the main control unit is disposed in a remoteplace from the manipulator. Besides, since the teaching data, etc. ofthe robot are also stored in the data storage device such as the harddisk, the flash memory, and the like in the main control unit, abattery, etc. need not be used to maintain the data. Furthermore, sincethere is also an auxiliary storage device provided in the main controlunit for backup of the data, the task of backing-up the data can beaccomplished easily and quickly, thereby enabling it to be prepared foran unforeseeable loss of the data.

Moreover, there is adopted a general-purpose data bus and ageneral-purpose interface for the data bus of the main control unit.This can allow use of general purpose peripheral devices such as adisplay device like a monitor, etc., an input device like a keyboard,etc., and a communications device like a network, etc. easily byconnecting them to the robot control apparatus, thereby enabling anexpansion of the system freely. In addition, since the robot controlapparatuses are connectable with generic network boards, this makes itpossible to concentrically supervise and control a plurality of therobot control apparatuses using communication means such as the network,in the case of a system operating a plurality of robots.

What is claimed is:
 1. A control apparatus for a robot having a drivingsource, comprising: a servo amplifier for controlling said drivingsource of said robot; an auxiliary control unit for outputting a drivingcontrol command to said servo amplifier; a communication means; and amain control unit for outputting a control command for, operation ofsaid robot to said auxiliary control unit through said communicationmeans, said main control unit being physically separatable from saidauxiliary control unit, thereby said main control unit is not affectedby an adverse environment of said auxiliary control unit; wherein saidauxiliary control unit is provided with a timer means, and a robotsuspension means for deactivating said servo amplifier if said auxiliarycontrol unit does not receive a robot control command from said maincontrol unit for a pre-established period of time or longer.
 2. Acontrol apparatus for a robot having a driving source, comprising: aservo amplifier for controlling said driving source of said robot; anauxiliary control unit for outputting a driving control command to saidservo amplifier; a communication means; and main control unit foroutputting a control command for operation of said robot to saidauxiliary control unit through said communication means, said maincontrol unit being physically separatable from said auxiliary controlunit, thereby said main control unit is not affected by an adverseenvironment of said auxiliary control unit; and a robot suspension meansin said auxiliary control unit, wherein said auxiliary control unittransmits a signal to said main control unit, and said robot suspensionmeans deactivates said servo amplifier if said main control unit doesnot return to said auxiliary control unit another signal correspondingto said signal.
 3. A control apparatus for a robot having a drivingsource, comprising: a servo amplifier for controlling said drivingsource of said robot; an auxiliary control unit for outputting a drivingcontrol command to said servo amplifier; a communication means; and amain control unit for outputting a control command for operation of saidrobot to said auxiliary control unit through said communication means,said main control unit being physically separatable from said auxiliarycontrol unit, thereby said main control unit is not affected by anadverse environment of said auxiliary control unit; wherein said maincontrol unit is provided with a timer means, and a determination meansfor determining either said auxiliary control unit or said communicationmeans is out of order, if said main control unit does not receive asignal from said auxiliary control unit for a pre-established period oftime or longer.
 4. A control apparatus for a robot having a drivingsource, comprising a servo amplifier for controlling said driving sourceof said robot; an auxiliary control unit for outputting a drivingcontrol command to said servo amplifier; a communication means; and amain control unit for outputting a control command for operation of saidrobot to said auxiliary control unit through said communication means,said main control unit being physically separatable from said auxiliarycontrol unit, thereby said main control unit is not affected by anadverse environment of said auxiliary control unit; wherein said maincontrol unit is provided with a determination means for determiningeither said auxiliary control unit or said communication means is out oforder, if a signal corresponding to another signal transmitted to saidauxiliary control unit from said main control unit is not returned fromsaid auxiliary control unit.
 5. A control apparatus for a robot having adriving source, comprising: a servo amplifier for controlling saiddriving source of said robot; an auxiliary control unit for outputting adriving control command to said servo amplifier; a communication means;a main control unit for outputting a control command for operation ofsaid robot to said auxiliary control unit through said communicationmeans, said main control unit being physically separatable from saidauxiliary control unit, thereby said main control unit is not affectedby an adverse environment of said auxiliary control unit; and acentralized control unit connected to said main control unit viacommunication means, wherein said centralized control unit is providedwith a timer means, and a determination means for determining eithersaid main control unit or said communication means is out of order, ifsaid centralized control unit does not receive a signal from said maincontrol unit for a predetermined period of time or longer.
 6. A controlapparatus for a robot having a driving source, comprising: a servoamplifier for controlling said driving source of said robot; anauxiliary control unit for outputting a driving control command to saidservo amplifier; a communication means; a main control unit foroutputting a control command for operation of said robot to saidauxiliary control unit through said communication means, said maincontrol unit being physically separatable from said auxiliary controlunit, thereby said main control unit is not affected by an adverseenvironment of said auxiliary control unit; and a centralized controlunit connected to said main control unit via communication means,wherein said centralized control unit is provided with a determinationmeans for determining that said main control unit or the communicationmeans is out of order, if a signal corresponding to another signaltransmitted to said main control unit from said centralized control unitis not returned from said main control unit.
 7. The robot controlapparatus according to claim 5, wherein said centralized control unitcomprises a computer.
 8. A method of controlling a robot comprising, inan auxiliary control unit, the steps of: receiving a robot controlcommand from a main control unit; converting said command into anothercommand to be transmitted to a servo amplifier; transmitting saidconverted command to said servo amplifier, with said main control unitbeing physically separatable from said auxiliary control unit so thatsaid main control unit is not affected by an adverse environment of saidauxiliary control unit; counting in said auxiliary control unit anon-receiving time of a command from said main control unit; making adetermination of a timeout when said non-receiving time becomes equal toor longer than a pre-established period of time; and deactivating saidservo amplifier if a timeout is determined.
 9. A method of controlling arobot comprising, in an auxiliary control unit, the steps of: receivinga robot control command from a main control unit; converting saidcommand into another command to be transmitted to a servo amplifier;transmitting said converted command to said servo amplifier, with saidmain control unit being physically separatable from said auxiliarycontrol unit so that said main control unit is not affected by anadverse environment of said auxiliary control unit; outputting a signalfrom said auxiliary control unit to said main control unit; receiving aresponse signal from said main control unit; verifying whether theresponse signal is a signal corresponding to the transmitted signal; anddeactivating said servo amplifier, if the response signal does notcorrespond to the transmitted signal.
 10. A method of controlling arobot comprising, in a main control unit, the steps of: generating arobot control command; outputting said robot control command to anauxiliary control unit through a communication means, with said maincontrol unit being physically separatable from said auxiliary controlunit so that said main control unit is not affected by an adverseenvironment of said auxiliary control unit; counting in said maincontrol unit a non-receiving time of a signal from said auxiliarycontrol unit; making a determination of a timeout when saidnon-receiving time becomes equal to or longer than a pre-establishedperiod of time; and determining either said auxiliary control unit orsaid communication means is out of order if a timeout is determined. 11.A method of controlling a robot comprising, in a main control unit, thesteps of: generating a robot control command; outputting said robotcontrol command to an auxiliary control unit through a communicationmeans, with said main control unit being physically separatable fromsaid auxiliary control unit so that said main control unit is notaffected by an adverse environment of said auxiliary control unit;outputting a signal from said main control unit to said auxiliarycontrol unit; receiving a response signal from said auxiliary controlunit; verifying whether the response signal is a signal corresponding tothe transmitted signal; and determining either said auxiliary controlunit or said communication means is out of order, if the response signaldoes not correspond to the transmitted signal.
 12. A method ofcontrolling a robot comprising, in a main control unit, the steps of:generating a robot control command; outputting said robot controlcommand to an auxiliary control unit through a communication means, withsaid main control unit being physically separatable from said auxiliarycontrol unit so that said main control unit is not affected by anadverse environment of said auxiliary control unit; counting in acentralized control unit connected to said main control unit viacommunication means a non-receiving time of a signal from said maincontrol unit; making a determination of a timeout when saidnon-receiving time becomes equal to or longer than a pre-establishedperiod of time; and determining either said main control unit or saidcommunication means is out of order if a timeout is determined.
 13. Amethod of controlling a robot comprising, in a main control unit, thesteps of: generating a robot control command; outputting said robotcontrol command to an auxiliary control unit through a communicationmeans, with said main control unit being physically separatable fromsaid auxiliary control unit so that said main control unit is notaffected by an adverse environment of said auxiliary control unit;outputting to said main control unit a signal from a centralized controlunit connected to said main control unit via communication means;receiving a response signal from said main control unit; verifyingwhether the response signal is a signal corresponding to the transmittedsignal; and determining either said main control unit or saidcommunication means is out of order, if the response signal does notcorrespond to the transmitted signal.